This 500 is used as a mortgage guarantee for the financial industry. In addition, you need an external guarantor. Maybe your supervisor has taken care of it for you.
No matter which company needs a deposit, this is the law of the financial industry. If the company suffers losses because of your mistakes, then this fee will be used to reduce the company's losses.
In addition, this guarantee will be returned to you when you leave your job.
Generally speaking, the purpose of finding a job is to make money, not to give money to others. No matter whether you can pass any internship in the end, you can earn hundreds of dollars on the grounds of deposit, which is not good.